JP4922862B2 - Bit holder device - Google Patents

Description

The present invention relates to a bit holder device capable tightened while magnetically attached and held the screws or the like to the bit body.

Conventionally, as a bit holder device that can be tightened while a screw or the like is magnetized and held on a bit body, for example, the one disclosed in Patent Document 1 is known.
The bit holder device of Patent Document 1 has a bit body that can be attached to an electric power tool, and a cylindrical sleeve that is externally fitted to the bit body. A member is attached. A circumferential groove is formed on the outer circumferential surface of the bit body, and an O-ring that can be engaged with the circumferential groove is provided on the inner circumferential surface of the sleeve. When the O-ring engages with the circumferential groove, the sleeve is engaged with the bit body in an externally fitted state.
Pamphlet of International Publication No. 05/000531

  By the way, in the bit holder device of Patent Document 1, the O-ring is elastically deformed and the bit body can be easily engaged with the sleeve. However, the use of an elastically deformable O-ring makes it easy to fit, but the sleeve will come off the bit body when an impact is applied unexpectedly, and the O-ring will lose its elasticity if used for a long time. May become easy to come off.

Further, in the bit holder device of Patent Document 1, it is necessary to form a recess for attaching an O-ring on the inner peripheral surface of the sleeve, and then to further fit the O-ring into the recess on each sleeve. There is. As a result, the number of parts is likely to increase, and the manufacturing process becomes complicated, resulting in a problem of increased assembly costs.
The present invention has been made in view of the above-described problems. By forming an engaging protrusion that engages with the circumferential groove of the bit body on the inner peripheral surface of the sleeve, the number of parts can be reduced and the manufacturing process can be reduced. It is an object of the present invention to provide a bit holder device that can keep assembly costs low by simplification .

In order to achieve the above object, the bit holder device of the present invention employs the following technical means.
That is, the bit holder device of the present invention has a cylindrical body that is fitted with a bit body having a cutting edge at the tip and a circumferential groove in the middle, and a magnetized member that magnetizes screws at the tip, and can be fitted over the bit body. And a sleeve provided with an engaging protrusion that engages with the circumferential groove and that protrudes radially inwardly on the inner circumferential surface, and has a length along the bit body axis direction in the circumferential groove. The sleeve has a length that allows the sleeve tip to move relatively from a position retracted from the tip of the bit body to a position advanced, and the sleeve includes a front portion to which a magnetizing member for magnetizing screws is attached, and a front portion. A sleeve disposed on the rear side in the longitudinal direction with respect to the portion, and the sleeve before being fitted to the bit body connects the front portion and the rear portion on the inner side in the radial direction, and the front portion and the rear portion. And the annular groove formed on the outer diameter side of the thin portion The sleeve after being fitted to the bit body includes an engagement protrusion formed integrally with the front and rear parts, and the annular groove is crushed to connect the front part and the rear part inside the diameter. The front portion and the rear portion are abutted on the outer diameter side of the engaging protrusion, and the engaging protrusion enters the circumferential groove and is fitted into the bit body in accordance with the formation of the engaging protrusion. Thus, characterized in that is, the engaging projection that bulges formed on the inner peripheral surface of the sleeve is disengaged from the bit body of the sleeve engages the circumferential groove of the bit body is prevented, a reduction in the number of components and Assembly costs can be kept low by simplifying the manufacturing process.

Further , the sleeve relatively moves following the movement of the screw in the axial direction (longitudinal direction), and the screw can be securely tightened while the screw is held by the magnetic adhesion member of the sleeve.
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Furthermore , it is possible to easily form an engagement protrusion bulging radially inward between the front part and the rear part simply by pressing the front part and the rear part close to each other in the longitudinal direction.

Furthermore , by compressing the sleeve before being fitted to the bit body along the longitudinal direction, the engagement protrusion can be easily formed on the inner peripheral surface of the sleeve. Therefore, the sleeve can be easily engaged with the bit body in a retaining state.

With the bit holder device of the present invention, the assembly cost can be kept low by reducing the number of parts and simplifying the manufacturing process .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention. The bit holder device 1 is attached to an electric rotary tool 2 such as an electric screwdriver, for example, and transmits / applies the rotational torque of the electric rotary tool 2 to a screw 3 or the like, and tightens or screws the screw 3 or the like. The bit holder device 1 includes a rod-shaped bit body 5 provided with a cutting edge 4 that can be engaged with a screw 3 at the tip, and a sleeve 6 formed in a cylindrical shape that can be fitted onto the bit body 5. .

For convenience of explanation, in the following explanation, the left side of FIG. 1 is the front side of the bit holder device 1 and the right side is the rear side. The direction away from the rotational axis R of the bit body 5 is defined as the radially outward direction, and the approaching direction is defined as the radially inward direction.
In the bit body 5, a cylindrical portion 8 is formed on the middle side following the cutting edge 4 on the front end side, and a shank portion 9 used for mounting on the electric rotary tool 2 is concentric with the cylindrical portion 8 on the rear side in the longitudinal direction. And is formed in a hexagonal column shape larger than the cylindrical portion 8. A stepped portion 10 having a surface perpendicular to the rotational axis R is formed between the cylindrical portion 8 and the shank portion 9, and the cylindrical portion 8 and the shank portion 9 are stepwise through the stepped portion 10. The diameter is formed to be large. A circumferential groove 11 used for engagement with the sleeve 6 is formed on the rear side of the cylindrical portion 8.

On the middle side in the longitudinal direction of the shank portion 9, a retaining portion 15 is formed in a groove shape in the circumferential direction. An annular locking member 18 is provided inside the electric rotary tool 2 so as to protrude radially inward. When the shank portion 9 is inserted into the electric rotary tool 2, the locking member 18 is prevented from coming off. And the shank portion 9 is prevented from coming off.
The cutting edge 4 is formed in a shape such as plus or minus according to the type of the screw 3 so as to be engageable with the screw 3. In this embodiment, the cutting edge 4 of a hex lobe bit is illustrated.

The circumferential groove 11 is formed near the stepped portion 10 (rear side) in the cylindrical portion 8 of the bit body 5 and is formed in a groove shape on the outer peripheral surface of the bit body 5 in the circumferential direction. The circumferential groove 11 is formed in a straight cylindrical shape whose outer diameter is smaller than the outer diameter of the cylindrical portion 8 other than the circumferential groove 11.
A tapered portion 12 is formed in an inclined shape on each of the front side and the rear side of the circumferential groove 11. The taper portion 12 connects the circumferential groove 11 and the outer peripheral surface of the bit body 5 so that the diameter continuously changes along the longitudinal direction.

The length along the longitudinal direction of the circumferential groove 11 is formed longer than an engagement projection 13 provided on a sleeve 6 described later, and the engagement projection 13 can engage with the circumferential groove 11 so as to be movable in the longitudinal direction. It is like that.
The sleeve 6 is formed in a cylindrical shape that can be fitted (covered) on the cylindrical portion 8 of the bit body 5. The sleeve 6 includes a front portion 23 provided with a magnetized member 19 for magnetizing the screw 3, and a rear portion 24 disposed on the rear side in the longitudinal direction (in contact with the front portion 23). The sleeve 6 includes a front portion 23 and a rear portion 24 connected to each other on the inner diameter side and an engaging protrusion 13 formed integrally therewith. Are abutted to form a front-rear abutting portion 20.

The front portion 23 is formed with an inner diameter in which a straight cylindrical mounting hole portion 16 is loosely fitted to the cylindrical portion 8 of the bit body 5.
An annular recess 17 is formed on the front side of the mounting hole 16 in the circumferential direction. A magnetizing member 19 is fitted in the annular recess 17, and a positioning projection 14 is formed on the front side of the annular recess 17 so as to restrict the forward movement of the magnetizing member 19 in the circumferential direction.

The magnetized member 19 is formed of a magnet capable of magnetizing the screw 3. The magnetized member 19 is formed in a ring shape that can be fitted into the annular recess 17 of the sleeve 6, and has an inner peripheral surface that is substantially flush with the inner peripheral surface of the mounting hole 16 in the longitudinal direction.
The rear portion 24 is formed in a cylindrical shape that can be externally fitted (covered) to the cylindrical portion 8 of the bit body 5 in the same manner as the front portion 23. The interior of the rear part 24 is a straight cylindrical mounting hole 16 having the same inner diameter as the front part 23 on the front side, and the rear part is formed in a tapered shape that is inclined toward the rear.

The engagement protrusion 13 is an annular protrusion that bulges inward from the inner peripheral surface of the mounting hole 16 between the front portion 23 and the rear portion 24, and the front / rear abutting portion 20 is the rotational axis of the bit body 5. It is formed along a direction perpendicular to R.
The engagement protrusion 13 enters the circumferential groove 11 of the bit body 5 and can engage with at least the tapered portion 12 on the front side of the circumferential groove 11 and is formed shorter in the longitudinal direction than the circumferential groove 11. ing. Thereby, the engagement protrusion 13 can be relatively moved in the longitudinal direction in the circumferential groove 11 while being engaged with the circumferential groove 11.

As shown in FIG. 1, when the engaging protrusion 13 of the sleeve 6 moves relative to the front side of the bit body 5 in the circumferential groove 11, the tip of the engaging protrusion 13 comes into contact with the inclined tapered portion 12. The relative forward movement of 6 is restricted.
As shown in FIG. 2, when the sleeve 6 is moved to the rear end side with respect to the bit body 5, the rear end of the sleeve 6 contacts the stepped portion 10 of the bit body 5 this time. As a result, the backward relative movement of the sleeve 6 with respect to the bit body 5 is restricted.

Thus, by engaging the engagement protrusion 13 of the sleeve 6 and the circumferential groove 11 of the bit body 5 so as to be relatively movable, the sleeve 6 can be moved in accordance with the screw 3, and the screw 3 The bit body 5 can be engaged with the screw 3 while holding the torque to transmit the torque.
The sleeve 6 of the bit holder device 1 is formed from a sleeve material 7. The sleeve material 7 is formed so as to become a sleeve 6 by being compressed (crimped) in the longitudinal direction and to be fitted to the bit body 5. That is, the sleeve material 7 is a “sleeve before being fitted into the bit body”.

As shown in FIG. 3, the sleeve material 7 includes a front part 23 having a magnetic adhesion member 19 at the tip, a rear part 24 arranged away from the front part 23 and the rear side in the axial direction, a front part 23 and a rear part. 24, and a thin portion 25 connecting the inner portion 24 and the thin portion 25.
In the sleeve material 7, a front regulating surface 21 and a rear regulating surface 22 that are perpendicular to the rotation axis R are formed at the rear end of the front portion 23 and the tip of the rear portion 24. The front regulation surface 21 and the rear regulation surface 22 are formed in parallel and facing each other with a distance therebetween. A thin portion 25 is continuously formed on the inner diameter side of the front side regulation surface 21 and the inner diameter side of the rear side regulation surface 22.

The thin-walled portion 25 is formed on the inner peripheral side of the cylindrical body by cutting the cylindrical body from the outer periphery and cutting the annular groove portion 26 having an arcuate inner surface. The thin-walled portion 25 bulges in the radially inward direction and becomes the engaging projection 13 by applying a compressive force in the longitudinal direction to the sleeve material 7 so as to crush the annular groove portion 26.
Next, an operation of compressing the sleeve material 7 to form the sleeve 6 and an operation of attaching the sleeve 6 to the bit body 5 will be described.

  First, the bit body 5 is inserted from the rear side of the sleeve material 7. In the sleeve material 7, the front portion 23, the thin portion 25, and the rear portion 24 are flush with each other on the inner diameter side, so that the bit body 5 can be inserted smoothly. The bit body 5 is inserted to the longitudinal position where the circumferential groove 11 corresponds to the thin portion 25 of the sleeve material 7, and then the sleeve material 7 is compressed from both ends of the sleeve material 7 with both held in this longitudinal position. Apply force in the direction you want.

  If it does in this way, the thin part 25 formed thinly also in the sleeve raw material 7 will deform | transform into a bulging shape toward the diameter inner side with a refuge. When the sleeve material 7 is compressed to a certain extent, the front side regulating surface 21 of the front part 23 and the rear side regulating surface 22 of the rear part 24 come into contact with each other, and the proximity movement along the longitudinal direction between the front part 23 and the rear part 24 is suppressed. Then, the compression processing (curvature deformation of the thin portion 25) is completed. Then, in the sleeve material 7 that has been subjected to the compression process, the thin portion 25 is deformed in a bulging shape from the inner peripheral surface of the mounting hole portion 16 to the inside of the diameter to form the engagement protrusion 13, and the sleeve material 7 becomes the sleeve 6. . At the same time as the deformation of the sleeve material 7 into the sleeve 6 is completed, the engaging protrusion 13 enters the circumferential groove 11 and the attachment of the sleeve 6 to the bit body 5 is also completed.

In this way, it is possible to easily form the sleeve 6 in which the engagement projections 13 are formed from the sleeve material 7 only by applying a compression force in the longitudinal direction after the sleeve material 7 is fitted to the bit body 5. In addition, the sleeve 6 can be attached to the bit body 5 in accordance with the formation of the sleeve 6. As a result, the assembly cost can be kept low by reducing the number of parts and simplifying the manufacturing process.
[Second Embodiment]
As shown in FIG. 4, the second embodiment of the bit holder device 1 is different from the first embodiment in the circumferential groove 11 formed in the bit body 5. That is, the circumferential groove 11 is formed so that the length along the longitudinal direction is substantially the same as the engagement protrusion 13.

In the second embodiment, since the lengths of the circumferential groove 11 and the engaging projection 13 along the longitudinal direction are substantially equal or slightly longer, the sleeve 6 is moved to the bit body 5 with little movement in the longitudinal direction. It is retaining. Accordingly, the magnetic force of the magnetic attachment member 19 is such that the magnetic lines of force concentrate on the cutting edge 4 of the bit body 5, and the screw 3 is magnetically attached only by the cutting edge 4.
The present invention is not limited to the above-described embodiments, and the shape, structure, material, combination, and the like of each member can be appropriately changed without changing the essence of the invention.

For example, although the cutting edge 4 of the bit body 5 is a hex lobe bit in the above embodiment, it can be formed in a shape such as minus or plus.
In the above embodiment, the bit body 5 is formed with the tapered portion 12 on the front side and the rear side of the circumferential groove 11, respectively, but the tapered portion 12 may be provided on the front side, and the front end of the circumferential groove 11 is rotated. It can also be formed on a plane orthogonal to the axis R.

  In addition, although the case where the hexagonal column-shaped shank part 9 engaged with the electric rotary tool 2 was illustrated in this embodiment, the electric rotary tool which has the hole corresponding to this with the shank part 9 formed in polygonal column shape other than a hexagonal column 2 can be engaged.

It is a partial cross section front view of 1st Embodiment of a bit holder apparatus. It is the same section sectional front view at the time of moving a sleeve to the back side. It is a partial cross section front view of a sleeve raw material. It is a partial cross section front view of 2nd Embodiment of a bit holder apparatus.

DESCRIPTION OF SYMBOLS 1 Bit holder apparatus 2 Electric rotary tool 3 Screw 4 Cutting edge 5 Bit body 6 Sleeve 7 Sleeve material 8 Cylindrical part 9 Shank part 10 Step part 11 Circumferential groove 12 Taper part 13 Engagement protrusion 14 Positioning protrusion 15 Retaining part 16 Mounting hole part Reference Signs List 17 annular recess 18 locking member 19 magnetized member 20 front-rear abutting portion 21 front regulating surface 22 rear regulating surface 23 front portion 24 rear portion 25 thin portion 26 annular groove portion R rotation axis

Claims (1)

A bit body having a cutting edge at the tip and a circumferential groove in the middle,
An engagement member is attached to the tip for magnetizing a screw, is formed in a cylindrical shape that can be externally fitted to the bit body, and protrudes radially inward from the inner peripheral surface to engage with the peripheral groove. A sleeve provided with a protrusion,
The length along the bit body axis direction in the circumferential groove is a length that relatively moves from the position where the tip of the sleeve is retracted relative to the tip of the bit body to the advanced position,
The sleeve has a front part to which a magnetizing member for magnetizing screws is attached, and a rear part arranged on the rear side in the longitudinal direction with respect to the front part,
The sleeve before being fitted to the bit body is formed on the outer side of the thin part, and the thin part integrally formed on the front part and the rear part, connecting the front part and the rear part on the inner diameter side. With an annular groove,
The sleeve after being fitted to the bit body has an engagement protrusion formed integrally with the front portion and the rear portion while the annular groove is crushed and connects the front portion and the rear portion on the inner diameter side. The front portion and the rear portion are abutted on the outer diameter side of the engaging protrusion, and the engaging protrusion enters the circumferential groove and is fitted to the bit body in accordance with the formation of the engaging protrusion. A bit holder device.

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